1. Field of the Disclosure
The present disclosure relates generally to communication systems, and more particularly to channel reuse in communication systems.
2. Description of the Related Art
In many widely used communication media, such as satellite systems, wireless systems, powerline, coaxial cable, and telephone line, a signal received by a station might be the sum of attenuated transmitted signals from a set of other stations, corrupted by distortion, delay, and noise. Such media, called multi-access media, are the basis for local area networks (LANs), metropolitan area networks (MANs), satellite networks, and cellular networks. In such communication systems, signals from stations other than the desired transmitter station are considered as interference at the receiver station. According to modern communication theory, a signal can be successfully received if the signal-to-interference-plus-noise ratio (SINR) at the receiver station is greater than a threshold. This gives the opportunity to improve the capacity of multi-access communication systems by allowing a set of stations that do not cause strong interference to each other, to reuse the same channel. The approach is called channel reuse.
The strength of electromagnetic signals attenuates along their propagation over various types of communication media. At a receiver station, when the interference signal strength is small enough such that the SINR at the station is sufficiently high, both the transmitter station and interfering station may transmit data over the same channel simultaneously. To support channel reuse, cellular systems can use a channel allocation mechanism to allow spatially apart stations to use the same channel at the same time. Typically, the cellular system is geographically divided into cells, each covered by a central controller, known as a base station. The set of available channels is partitioned into subsets called reuse groups. These channel groups may then be assigned to the cells in such a way that cells with the same group of channels are not close together. How close the co-channel cells are with each other may depend on the SINR requirement.
Although such a channel reuse mechanism may work well in cellular systems, it may require the service provider to perform the centralized channel planning. Such a requirement may be difficult to meet in many ad hoc multi-access communication systems, such as home networks that are deployed and managed by individual customers, and use wireless powerline, coaxial cable, and/or phone lines as the communication media. For example, a large number of home units may exist in an area. Due to the lack of a central entity performing channel planning, the corresponding channel allocation problem may be highly complex to solve with the same channel planning mechanism used in cellular systems. In addition, as the usage of each network could be highly dynamic, static (or pre-specified) channel allocation could significantly affect spectrum efficiency due to the waste (e.g., under usage) of some channels.